Scoliosis is a spinal deformity affecting many people. Current surgical treatment involves affixing long fusion rods to the spine by pedicle screws. The rod system is intended to force the deformed spine into a more healthy position. Other spinal disorders which are often treated by fusion include hyperkyphosis and hyperlordosis.
PCT Patent Application PCT/US2013/020454 describes a spinal cage that has a rotational pivot and a mechanism to allow rotation in one direction while preventing rotation in the opposite direction.